1. Field of the Invention
The present invention relates to a conveying guide which guides a sheet, a sheet conveying apparatus including the conveying guide, and an image forming apparatus including the sheet conveying apparatus.
2. Description of the Related Art
The image forming apparatus includes a pair of conveying guides and a conveying path. The conveying guides are configured to guide both sides of a sheet, and the conveying path is provided as a roller or a belt. In the case where any projection or catch, which may interrupt the sheet conveyance, is formed on a conveying surface of the conveying guide, the projection or catch may cause a sheet jam or a sheet corner folding. Therefore, the conveying surface needs to be formed smooth.
However, the conveying guide is required to include a hole for projecting a conveying roller from the conveying surface or a slit provided at a junction of the conveying paths. To solve this, some techniques have been proposed as follows: in Japanese Patent Laid-Open No. 2006-347678, a biasing member is provided to guide a sheet so that a front end of the sheet may be away from a hole formed on a conveying surface, and in Japanese Patent Laid-Open No. 2004-67321, air is applied to bias a sheet toward a conveying path.
Meanwhile, beside the above-described functional shapes such as the hole and the slit, there are many cases where a bearing which supports a conveying roller is fitted into the conveying guide and its bearing support portion is attached to a back surface of the conveying surface to support the bearing. Recently, in particular, as higher image quality and speed-up are required in the image forming apparatus, there are an increasing number of cases where the conveying guide is formed from a plate so as to prevent a sheet from clinging to the conveying guide due to electrification.
Further, in the case where a support portion such as the bearing support portion is integrally formed by bending up from the conveying guide, a bend relief is made in course of the bending-up process and an edge of the bend relief appears on the conveying surface. Particularly, since the bearing support portion is bent up in a direction orthogonal to a sheet conveying direction, the edge of the bend relief may project in a direction in which the conveying sheet may get caught. To solve this, a method is generally employed in which an additional member which supports the bearing is attached to the conveying guide by welding or screwing so as to support the bearing and avoid the process on the conveying surface.
However, in this configuration of attaching the additional member, the number of parts increases, resulting in cost increase. Further, the weight of the parts will increase, which may hinder the improvement of user's operability and serviceman's workability.